Remote sensing of in-ground fluid level apparatus

ABSTRACT

A fluid pump apparatus includes a pump chamber in a wellbore, a drive line capable of transferring a gas pressure to the pump chamber, a control system, an exhaust line, and a pressure sensor. The pressure sensor is capable of remotely sensing gas pressure in the exhaust line and providing communication to the control system. The control system is capable of determining when the fluid level in the pump chamber is full or near full based on input from the pressure sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

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REFERENCE TO SEQUENCE LISTING

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BACKGROUND

1. Field of the Invention

The invention generally relates to an in-ground fluid pumping system. More particularly, the invention is related to an apparatus for remotely sensing the fluid level in a pump chamber.

2. Description of the Related Art

In-ground fluid pumping systems are employed to extract petroleum oil, water, or other liquids from within the earth. These pumping systems are often placed in a drilled well to efficiently extract fluids from tens to hundreds of meters below the surface of the earth (ground level). In many cases, a blend of fluids, such as oil and water, are extracted, in addition to natural gas and contaminates such as sand. As such, in-ground wells require robust pumping systems to reduce the potential of various hazards while also avoiding premature wear due to the transfer of abrasives in the fluid.

Traditional wells date back to the 1920's, which employ a pumpjack fluid extraction system. A pumpjack uses a walking beam, fixed above ground, which continuously actuates a piston connected by a series of connecting rods (sucker rods). These are mechanically intensive pump systems, having moving components spanning deep into the well which require maintenance due to wear, scaling, and corrosion. Their mechanical nature causes difficulties in remotely sensing fluid levels deep in the well.

More recently, a gas displacement pump has been introduced as an alternative to a traditional pumpjack well pump for some applications. Gas displacement pump systems collect a volume of fluid in a pump chamber near the bottom of the well, which is then pumped to a receiving tank using gas pressure. Gas displacement wells have fewer moving parts, compared to pumpjack systems. As such, gas displacement wells are generally less expensive than pumpjack systems to install and operate.

These gas displacement pumps are more conducive to having electrically connected fluid level sensing components in the well. The lack of reciprocating components improve the capability of electrically connected sensing systems. One electrical sensing system relies on limit switches in the pump chamber to sense near full and near empty fluid levels. These switches are positioned essentially at the bottom of the well, requiring electrical cables connected from above ground to hundreds of meters deep. Normally two switches are positioned in the pump chamber to sense high and low fluid levels. The high fluid level corresponds to a near full condition and the low fluid level corresponds to a near empty condition. When high fluid level is detected, the pump chamber is ready to be pressurized with gas to drive the fluid towards the surface. When a near empty fluid level is detected, pumping towards the surface is complete and the pump chamber gas is exhausted to allow the chamber to refill with fluid from the wellbore. Since conventional high and low sensors are located in the pump chamber, they are directly exposed to oil, water, gas and abrasives. These switches and electrical connections pose serious reliability and safety concerns.

It is preferred that electrical components are not exposed to oil or gas. It is also preferred that electrical cables, if any, do not extend essentially the full depth of the well. It is further preferred that a fluid evacuation rate, such as barrels of oil per day (bpd), be maximized.

SUMMARY

The present invention provides a fluid pump apparatus for use in a gas displacement pump system capable of sensing when the fluid level in a pump chamber is full or near full without a sensor located in the pump chamber. The present invention teaches a novel apparatus for detecting pump chamber full or near full with a pressure sensor located in a gas line. The pressure sensor can be a great distance from the pump and therefore can be located on the surface where the conditions are not harsh and maintenance is facilitated.

A first embodiment of the present invention provides a fluid pump apparatus for use in a gas displacement pump capable of sensing a fluid level in a pump chamber using a full complement of valves, a down-hole exhaust valve, and a vacuum pump.

A second embodiment of the present invention provides a fluid pump apparatus for use in a gas displacement pump capable of sensing a fluid level in a pump chamber using a minimum set of valves, all on or above the earth surface, and a venturi.

Both the first and second embodiments are capable of sensing near-full fluid level in the pump chamber when the pump chamber gas pressure is either above or below atmospheric pressure, and having a sensing means tens to hundreds of meters from the fluid level.

Features and advantages of the present invention will be more understood through the detailed description and in reference to the figures which follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is an elevation view, not to scale, schematically representing a first embodiment of a fluid pump apparatus;

FIG. 1 b is taken from View A-A of FIG. 1 a showing a top view, not to scale, of schematically represented features;

FIG. 2 a shows FIG. 1 a in a negative pressure fill state;

FIG. 2 b shows FIG. 1 a in a near-full sense state following negative pressure fill;

FIG. 3 a shows FIG. 1 a in a positive pressure fill state;

FIG. 3 b shows FIG. 1 a in a near-full sense state following positive pressure fill;

FIG. 4 a is an elevation view, not to scale, schematically representing a second embodiment of a fluid pump apparatus;

FIG. 4 b is taken from View B-B of FIG. 4 a showing a top view, not to scale, of schematically represented features;

FIG. 5 shows FIG. 4 a in a negative pressure fill and sense state;

FIG. 6 shows FIG. 4 a in a positive pressure fill and sense state;

DETAILED DESCRIPTION

It is to be understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention. It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Further, the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. It is also to be understood that the use of the term “fluid” denotes a liquid, but “fluidic”, “fluidic communication”, “fluidically coupled” or like terms can denote a liquid or a gas as is commonly used in the industry.

An overall description of the pumping system will be described, corresponding to FIGS. 1 a-b. Turning to FIG. 1 a, fluid pump apparatus 11 a comprises a fluidic system 21 (normally described as a “well”) formed of a wellbore 10 positioned in an earth formation 15 containing fluid such as oil or water, but may also include natural gas and contaminants such as sand, at a generally static fluid level 20. The wellbore 10 is generally a tubular steel casing extending from an upper end near an earth surface 25, terminating at a lower end tens to hundreds of meters into the earth formation 15. The wellbore 10 may include perforations 30 near the lower end on the sides and bottom surface, which permits fluid to enter.

A wellbore casing is normally used for deep wells to preserve their shape, but in some instances, the integrity of the surrounding earth is adequately sound without a casing. For example, a well (such as fluidic system 21) drilled into solid rock or tight clay may not require a separate casing. The present invention will function adequately in these instances, therefore is within the scope of what is described herein as a fluid pump apparatus (11 a or 11 b).

Returning again to FIGS. 1 a-b, pump chamber 35 is positioned near the bottom of the wellbore 10 proximate the perforations 30. The pump chamber 35 includes a pump chamber bottom 36, a chamber top 37, and generally circular sides. The pump chamber bottom 36 includes a normally round hole, providing a fluid inlet 40. The pump chamber bottom 36 may be flat, conical, convex, concave, or other such shape. A conically shaped pump chamber bottom 36 is shown throughout the figures. The chamber top 37, more clearly shown in FIG. 1 b, includes a fluid outlet port 45 and a gas port 50. The chamber top 37 is preferably a separate component mechanically coupled and fluidically sealed to the pump chamber 35.

Within the pump chamber 35 is a fluid inlet check ball 55 held in position by retainers (not shown) which is common for check ball designs. The retainers allow movement of the fluid inlet check ball 55 but contain it to a position capable of sealing against a fluid inlet ball seat 56 when a force balance on the fluid inlet check ball 55 favors the sealing position. Also within the pump chamber 35 is a fluid outlet port 45 mechanically coupled to the chamber top 37. The fluid outlet pipe 48 is a hollow pipe of substantially smaller diameter than the pump chamber, which provides a fluidic path from an intake port 46 of the pump chamber 35 to a fluid outlet exit port 47 positioned to dispense the pumped fluid to a receiving tank 60. The fluid outlet pipe 48 may optionally be formed integrally to the pump chamber 35. The fluid outlet pipe 48 includes a fluid outlet check ball 38, which forms a seal against fluid outlet ball seat 42 to prevent fluid in the fluid outlet pipe 48 from flowing back to the pump chamber 35.

The receiving tank 60 is positioned near the earth surface 25, normally referred to as “ground level”. It may be buried below the earth surface 25, may be positioned above the earth surface 25, or may be on a mobile transport such as a truck (not shown) or trailer (not shown). The receiving tank 60 may be an open trough design, as shown in the figures, or may be a closed or partially closed shape.

Also shown in FIG. 1 a is a pneumatic system 31. A compressed gas supply 65 is fluidically coupled to a drive line 70. A compressed gas supply 65 may be a gas compressor, wherein gas is compressed on demand, or may be bottled gas. The gas may be air, natural gas, or an inert gas such as nitrogen or argon. The drive line 70 terminates at gas port 50 shown in View A-A (FIG. 1 b) which is a part of chamber top 37. In-line with the drive line 70 is valve 75, which controls the flow of gas through the drive line 70 and into the pump chamber 35, also isolating the compressed gas supply 65 from the pump chamber 35. An exhaust line 110 branches off the drive line 70 providing a vent to an exhaust chamber (not shown) with low resistance to gas flow, normally above the earth surface 25. The exhaust chamber may be a tank capable of receiving gas, or it be may be the atmosphere. A tank may be used to capture and possibly recycle gas, particularly if an inert gas such as nitrogen or argon is used. A tank may be configured to perform in similar fashion to the atmosphere, having a large volume capacity and having means for providing gas to pneumatic system 31 on demand.

In parallel with exhaust line 110 is pressure sensor 105, capable of measuring positive and negative pressure in this line. Also in parallel with exhaust line 110 is vacuum line 80, which is coupled to a vacuum device such as vacuum pump 85, capable of providing a vacuum means to exhaust line 110 and pump chamber 35. In-line with exhaust line 110 is valve 115, which controls the flow of gas through the exhaust line 110 and fluidically isolates the exhaust line 110 from an exhaust chamber. Also in-line with the exhaust line 110 is valve 90 which controls the flow of gas through the exhaust line 110 and isolates the pump chamber 35 from the pressure sensor 105.

Valves 75 and 90 are shown in a “down-hole” configuration, wherein these valves are positioned in the wellbore 10 which may exceed 610 m (2000 ft.) below the earth surface 25. In an alternate configuration, these valves may be integrated with additional features such as chamber top 37. It should be noted, however, that the wellbore 10 may have an internal diameter as small as 10 cm (4 in.). Therefore, the usable outside diameter of down-hole devices is about 7.7 cm (3 in.), which is the primary limitation to locating control components below the earth surface 25.

Valve 115 may be electronically or pneumatically controlled as further described in a subsequent paragraph. Alternately, valve 115 may be replaced by a check valve (such as normally closed check valve 116 shown in FIG. 4 a) which is capable of operation passively with no external controls. For some embodiments, or some operating conditions, a passive exhaust valve may provide a “failsafe”, capable of preventing an unsafe pressure buildup in the event of an electrical or control system 120 malfunction. A passive exhaust may also be preferred for embodiments in which providing an electrically or pneumatically controlled valve is impractical.

A portion of pneumatic system 31 may be designed to provide service to multiple wells (such as fluidic systems 21) in a “hub and spoke” configuration. A pneumatic hub 34 may consist of at least the compressed gas supply 65, and may optionally include a vacuum device such as vacuum pump 85. The pneumatic hub 34 may be configured in a first location, providing service to a well or to multiple wells in a second, third, or any number of well locations (“spokes”) within the practical limits of cost, distance, fluidic friction, and the like. Such a configuration may be practical due to cost and maintenance efficiencies, or in cases in which access to a well may be limited by, for example, the earth surface 25 terrain, environmental sensitivities, or personal privacy.

FIG. 1 a also shows a control system 120 having representative control lines communicating with “control components”. Broken control lines are shown for clarity. “Control components” generally include electrically controlled devices in the pneumatic system 31. In the figure, this includes valve 75, valve 90, valve 115, valve 100, pressure sensor 105, compressed gas supply 65, and vacuum pump 85. (Each of the valves are referred to generally as “active valve components”.) The control system 120 may include multiple sub-systems to provide, for example, supervisory control, data acquisition, and programmable logic. This system is generally capable of receiving electrical signals, processing the signals, then producing an output signal capable of controlling or reporting. In one aspect of this invention, the output signal is capable of indicating a near full condition in the pump chamber. More particularly, pressure sensor 105 remotely measures a pressure in exhaust line 110, then provides a corresponding electronic signal to the control system 120. The control system 120 relies on programmable logic to interpret the electrical signal, and to determine if an action should be performed. For example, if the control system 120 interprets a pressure, or change in pressure, corresponding to thresholds defined in the programmable logic, a change in the state of valves or pumps may occur. In one instance, once a near full condition is determined by the control system 120, a change to a fluid pumping state may occur by opening valve 75 to allow fluidic communication of the compressed gas supply 65 to the pump chamber 35, or by closing valve 90 to isolate pump chamber 35 from exhaust line 110.

The pressure sensor 105 is robust in operation. It is capable of sensing a pressure in an exhaust line having a number of bends, angles, or restrictions with no degradation in the quality of the sensed pressure.

In application, “near full” may indicate a variable level depending on the behavior of the pressure sensor 105, the impedance of pneumatic system 31 and the logic sensitivity programmed into the control system 120. For most applications, is not necessary to optimize the design to a precise level prior to initiating the pump cycle. Near full may indicate 100% full for one well, 90% full for another, and 80% full for yet another. An individual well may also change with time, resulting in “near full” changing from 90% to 85% or 95% while still within the spirit and scope of a “near full” condition. Even in a hub and spoke configuration, wherein a pneumatic hub 34 is shared among multiple wells, a range of “near full” thresholds may occur from well to well.

Returning again to a discussion of output signals, an output signal may alternately communicate with one or more intermediate devices wherein additional logic or actions may determine if, or when, a change in the state of valves or pumps will occur. For example, an intermediate device may include an electrical device (not shown) for providing, for example, a number, a light, a level, a sound, a haptic response, a different output signal, or any combination thereof to a user or to a secondary control system, which may be an electrical or a pneumatic control system.

In addition to controlling the systems described herein, control system 120 may also include monitoring of local environmental conditions such as weather, security, and safety, and may provide a means for external data monitoring and reporting, via wired or wireless communication. Depending on the control configuration, more than one control line may be used. Electrical lines may pass through the control system 120, or may communicate directly with any of the control components. The actual wiring of each control component is considered designer's choice, and is known by those skilled in the art.

Now describing the active valve components in more detail, each of the valves may be electronically controlled. Exemplary electronically controlled valves may include solenoid valves, ball valves, proportional control valves, stepper controlled valves, and the like. Alternately, pneumatically controlled valves may also be used. In these cases, an additional gas line may be required to actuate the valve. Control of the additional gas line may further require an electronically controlled valve, but such pneumatically controlled valves may have advantages in more severe operating environments or in cases in which safety regulations prohibit the use of electrical communication.

Continuing to reference FIG. 1 a, a check valve 95 may optionally be included in-line with drive line 70, which will isolate fluid from the pneumatic system 31 and providing a more definite output signal from pressure sensor 105 to control system 120 when a pressure change is measured. The moving component of the check valve 95, float 96, is designed to be buoyant in the fluid by having a specific gravity less than or equal to the specific gravity of the fluid. The float 96 may be a sphere, such as shown in the figures, but may have various shapes. Check valve 95 protects pneumatic system 31, by allowing air or other gas to flow into or out of pump chamber 35 with minimal fluidic resistance. The orientation of the check valve 95 is such that gravity causes the float 96 to fall away, providing a “normally open” valve, allowing the flow of gas. The float 96 closes when a fluid level (not shown in FIG. 1 a) rises, causing the check valve 95 to seal, preventing the upward flow of fluid above the check valve 95. Upon sealing, the pressure sensor 105 will sense a sudden change in pressure, providing a positive indication that the pump chamber 35 is near full.

In many applications, the pressure sensor 105 will remotely sense a fluid level a distance of at least 30.5 m (100 ft.) above pump chamber 35. In other applications, the pressure sensor 105 will be a distance of at least 305 m (1000 ft.) above pump chamber 35. Thus, the pressure sensor 105 in combination with the control system 120 is capable of remotely sensing a fluidic level in the pump chamber by reading the gas pressure in the exhaust line 110.

Fluid levels in fluidic system 21 will now be introduced into FIGS. 2 a-b and 3 a-b. In addition, the states of the active valve components will be shown in more detail.

In FIG. 2 a, a negative pressure fill state is described, corresponding to FIG. 1 a. A wellbore fluid level 32 is shown below chamber top 37. For pump chamber fluid level 33 to fill (or nearly fill) the pump chamber 35, a vacuum is created according to the following description: Vacuum pump 85 is engaged, valve 100 and valve 90 are open to allow flow, and check valve 95 is in a normally open state, causing a vacuum in pump chamber 35, as shown by vacuum arrows 44. (For a well using a pneumatic hub 34, vacuum pump 85 may already be actuated.) Valves 75 and 115 are closed, preventing flow. Fluid is pulled from wellbore 10 by flowing through fluid inlet 40, past fluid inlet check ball 55, and into pump chamber 35 causing the pump chamber fluid level 33 to rise.

Turning now to FIG. 2 b, a near-full sense state after negative pressure fill is described, corresponding to FIG. 1 a. Control system 120 will be conditioned to determine an appropriate time duration to predict the pump chamber fluid level 33 to nearly fill pump chamber 35. Once near full is predicted, valve 100 will close (preventing flow), then pressure sensor 105 will provide more than one signal to control system 120, spaced apart by a time delay determined by the control system 120. Control system 120 will calculate any difference in signals. A small difference indicates the pump chamber fluid level 33 is stable and is not rising. When the fluid level 33 is stable, then the negative pressure reported by pressure sensor 105 is compared to a threshold and if below the threshold, then the fluid chamber is near full. If the stable pressure is not below the threshold, the pump chamber has not achieved a near full condition. The near full stable pressure threshold is a negative number. The time delay is dependent on the responsiveness of the pneumatic system 31 which is, in part, determined by the depth of the fluidic system 21, the rate of change of pump chamber fluid level 33, and the pneumatic impedance of the pneumatic system 31. If control system 120 determines that “near full” has not been achieved, a return to the negative pressure fill state may be required.

The control system 120 is designed to detect “near full”, then evacuate the pump chamber 35 with minimal delay, providing a maximized fluid evacuation rate. In addition, the negative pressure fill described herein further improves the fluid evacuation rate, thereby maximizing fluid production even in low production wells.

FIG. 3 a shows FIG. 1 a in a positive pressure fill state, wherein the wellbore fluid level 32 is above the pump chamber 35, thereby allowing the positive head pressure to provide the force for filling the pump chamber 35. Thus, valves are controlled simply to provide a vent to an exhaust chamber. In this embodiment, valve 100 is closed, isolating exhaust line 110 from vacuum pump 85. In the case of a pneumatic hub 34, vacuum pump 85 may continue to be engaged to supply vacuum pressure to other wells. For a vacuum pump 85 dedicated to a well, it would likely be disengaged. Valves 115 and 90 are open, providing a vent from pump chamber 35 to an exhaust chamber, enabling pump chamber fluid level 33 to rise with minimal fluid resistance.

FIG. 3 b describes a near-full sense state following the positive pressure fill state. Control system 120 will be conditioned to determine an appropriate time duration to predict when the pump chamber fluid level 33 should be nearly full in the pump chamber 35. Once near full is predicted, valve 115 changes state from opened to closed, isolating exhaust line 110 from the an exhaust chamber. Pressure sensor 105 will then provide more than one signal to control system 120, spaced apart by a time delay. As previously described, control system 120 will determine if the pump chamber 35 is near full, or if a return to the previous fill state is needed. In the positive pressure fill case, the pressure threshold indicating near-full is a positive number. When sensor 105 detects a pressure in the sense state that is below the threshold, then near-full is detected. The control system 120 is optimized to sense a near full condition, then immediately evacuate the pump chamber 35, improving the fluid evacuation rate.

FIGS. 4 a-b provide a fluid pump apparatus 11 b, corresponding to the second embodiment. Fluid levels in the fluidic system 21 are not shown for clarity. In FIG. 4 a, the fluidic system 21 is similar to FIG. 1 a, with exceptions noted.

Pneumatic system 41 will be discussed relative to pneumatic system 31 shown in FIG. 1 a. The compressed gas supply 65, which may be a gas compressor or bottled gas as previously described, is fluidically coupled to the drive line 70 and to a vacuum device. In this configuration, the vacuum device shown is a venturi 86. The drive line 70 terminates at gas port 50 shown in View B-B (FIG. 4 b) which is a part of chamber top 39. In-line with the drive line 70 is valve 75, which controls the flow of gas through the drive line 70 and into the pump chamber 35. It should be noted that valve 75 is shown above ground (above earth surface 25), in contrast to the down-hole position shown in FIG. 1 a. Valve 75 may be in either position or any position in between. This is designer's choice based on practical implementation constraints dependent on the specific well configuration. In parallel with exhaust line 110 is vacuum line 80, which is coupled to the venturi 86. Venturi 86 is capable of creating a vacuum from a positive pressure source such as compressed gas supply 65. Venturi 86 is independently controlled by valve 125, which provides pressure on-demand to the venturi 86, resulting in a vacuum created by the well-known venturi effect. In operation, venturi 86 provides a vacuum to vacuum line 80, causing a vacuum in exhaust line 110 and pump chamber 35, which is capable of being sensed by pressure sensor 105. In FIG. 4 a, pneumatic hub 34 includes compressed gas supply 65, valve 125, and venturi 86.

The exhaust line 110 is shown directly coupled to the chamber top 39, in contrast with branching off of drive line 70, as previously shown in FIG. 1 a-b. Check valve 95 is not shown in the figure.

FIG. 4 b shows a top view of chamber top 39 taken from FIG. 4 a, view B-B. Chamber top 39 includes fluid outlet port 45 and gas port 50, but also includes a second port, gas port 51.

Returning again to FIG. 4 a, exhaust line 110 is shown in-line with check valve 116. This valve is normally closed, which passively inhibits the flow of gas in, but enables the flow of gas out of, exhaust line 110. As is common with check valves, there is a “cracking pressure” below which, the check valve will remain closed. A preferred cracking pressure is about 70 cm water column (1 psi).

Pressure sensor 105 is shown positioned in parallel with vacuum line 80, which is in parallel with exhaust line 110. It should be noted that the pressure (positive or negative) in exhaust line 110 will be essentially equivalent at least between valve 90, venturi 86, and check valve 116, therefore the pressure sensor 105 may be functionally positioned between these components. Practical considerations will likely determine the location of this sensor, although it is preferred that the pressure sensor 105 will be positioned above the pump chamber 35. It is most preferred that pressure sensor 105 be located above the earth surface 25, which will likely will be tens to hundreds of meters above pump chamber 35.

Fluids in fluidic system 21 will now be introduced into FIGS. 5 and 6, including the states of the active valve components.

FIG. 5 shows a negative pressure fill state and simultaneous sense state for fluid pump apparatus 11 b shown in FIG. 4 a. In this instance, the wellbore fluid level 32 is shown below chamber top 39. For pump chamber fluid level 33 to fill (or nearly fill) the pump chamber 35, a vacuum is created by supplying a pressure from compressed gas supply 65, through valve 125 (which is in an open state to allow gas flow), through venturi 86, then exhausted to the an exhaust chamber. This airflow pulls air from vacuum line 80 according to the venturi effect. Check valve 116, which is normally closed, remains closed due to the vacuum force acting upon it. Valve 90 is open to allow vacuum to the pump chamber 35, causing a vacuum to act on the pump chamber fluid level 33 as shown by vacuum arrows 44. Given the minimal valves in this configuration, there is no means for providing a closed volume from which to sense pressure. However, the apparatus provides a means of pressure sensing while gas is exhausted to an exhaust chamber. In this instance, pressure sensor 105 may sense continuously or during time intervals as determined by control system 120. As pump chamber fluid level 33 rises, the volume of gas in the pump chamber 35 decreases, allowing for higher levels of vacuum (negative pressure) in exhaust line 110. When the vacuum level reported by pressure sensor 105 is above a threshold (vacuum higher than the threshold is detected), then the fluid chamber is near full.

FIG. 6 shows a positive pressure fill state for fluid pump apparatus 11 b shown in FIG. 4 a in which the wellbore fluid level 32 is above the pump chamber 35. Thus, valves are controlled simply to provide a vent to an exhaust chamber to allow wellbore fluid to enter the pump chamber. In this embodiment, valve 125 is closed, isolating exhaust line 110 from compressed gas supply 65. In the case of a pneumatic hub 34, compressed gas supply 65 may continue to be engaged to supply gas pressure to other wells. For a dedicated well, it would likely be disengaged. Valve 90 is open, providing a vent from pump chamber 35 to an exhaust chamber, enabling pump chamber fluid level 33 to rise with minimal fluidic resistance. As previously described, the minimal valves in this configuration do not provide a closed volume from which to sense pressure. However, the apparatus provides a means of pressure sensing while gas is displaced from the pump chamber 35, exhausting to the atmosphere. In this instance, pressure sensor 105 may sense continuously or during time intervals as determined by control system 120. As the pump chamber fluid level 33 rises, the volume of gas (such as air) in the pump chamber 35 is vented through the venturi 86 to an exhaust chamber (the venturi will allow air passage even when not energized). The venturi 86 causes a flow restriction, resulting in a backpressure in the fluidic system. This is sensed by the pressure sensor 105 as a low level positive pressure. A sensor having an increased sensitivity is preferred for this configuration. The pressure reported by pressure sensor 105 is compared to a threshold and if below the threshold, then the fluid chamber is near full.

It will be appreciated by those skilled in the art that valves may be capable of control via a pneumatic controller.

Systems may be configured differently than the figures show while falling within the scope of the present invention. For example, redundant valves may be used in any fluidic line. In another example, vacuum line 80 may have essentially zero length. In yet another example, vacuum devices such as vacuum pump 85 and venturi 86 may be interchanged.

It is contemplated, and will be clear to those skilled in the art that modifications and/or changes may be made to the embodiments of the invention. Accordingly, the foregoing description and the accompanying drawings are intended to be illustrative of the example embodiments only and not limiting thereto, in which the true spirit and scope of the present invention is determined by reference to the appended claims. 

What is claimed is:
 1. A fluid pump apparatus comprising: a. a pump chamber located in a wellbore and having a fluid inlet, a fluid outlet port, and at least one gas port, and b. an exhaust line providing fluidic communication from said gas port to an exhaust chamber located a distance above said pump chamber, and c. a control system capable of receiving an electrical input, processing said electrical input, and producing an electrical output signal, and d. a pressure sensor in fluidic communication with the exhaust line and in electrical communication with the control system, and e. said control system is capable of receiving an electrical input from said pressure sensor, processing said electrical input, and producing an electrical output signal capable of indicating a near full condition in said pump chamber.
 2. The fluid pump apparatus of claim 1, further comprising: a. a vacuum device, capable of providing negative pressure gas, in fluidic communication with said exhaust line, and b. a valve capable of fluidically isolating said exhaust line from said exhaust chamber.
 3. The fluid pump apparatus of claim 2, further comprising: a. a compressed gas supply capable of providing positive pressure gas, and b. a drive line in fluidic communication from said compressed gas supply to said gas port, and c. a valve capable of fluidically isolating said pressure sensor from said pump chamber, and d. a valve capable of fluidically isolating said compressed gas supply from said pump chamber.
 4. The fluid pump apparatus of claim 1, further comprising: a. a compressed gas supply capable of providing positive pressure gas, and b. a drive line in fluidic communication from said compressed gas supply to said gas port, and c. a venturi in fluidic communication with said compressed gas supply and with said exhaust line, and d. a valve capable of fluidically isolating said venturi from said compressed gas supply, and e. a valve capable of fluidically isolating said pressure sensor from said pump chamber, and f. a valve capable of fluidically isolating said compressed gas supply from said pump chamber.
 5. The fluid pump apparatus of claim 3, further comprising: a. a normally open check valve including a float, wherein said float is capable of allowing the bi-directional flow of gas and downward flow of liquid, but preventing the upward flow liquid.
 6. The fluid pump apparatus of claim 4, further comprising: a. a normally open check valve including a float, wherein said float is capable of allowing the bi-directional flow of gas and downward flow of liquid, but preventing the upward flow of liquid.
 7. The fluid pump apparatus of claim 1, further comprising: a. said pressure sensor positioned at least 30.5 m (100 ft.) above said pump chamber.
 8. The fluid pump apparatus of claim 3, wherein: a. said output signal is capable of communicating with an intermediate device being at least one member of the group consisting of a number, a light, a level, a sound, a haptic response, and a different output signal.
 9. The fluid pump apparatus of claim 3, wherein; a. said output signal is capable of controlling a valve to enable fluidic communication from said gas supply to said pump chamber.
 10. The fluid pump apparatus of claim 3, wherein; a. said output signal is capable of controlling a valve to fluidically isolate said exhaust line from said pump chamber.
 11. The fluid pump apparatus of claim 3, wherein; a. said exhaust chamber being at least one of a tank and atmosphere.
 12. A fluid pump apparatus comprising: a. a pump chamber located in a wellbore and having a fluid inlet, a fluid outlet port, and a gas port, and b. an exhaust line providing fluidic communication from said gas port to an exhaust chamber located a distance above said pump chamber, and c. a control system capable of receiving an electrical input, processing said electrical input, and producing an electrical output signal, and d. a pressure sensor in fluidic communication with the exhaust line and in electrical communication with the control system, and e. said pressure sensor capable of providing one or more electrical signals to said controller corresponding to a near full condition in said pump chamber.
 13. The fluid pump apparatus of claim 12, further comprising: a. a vacuum device, capable of providing negative pressure gas, in fluidic communication with said exhaust line, and b. a valve capable of fluidically isolating said exhaust line from said exhaust chamber.
 14. The fluid pump apparatus of claim 13, further comprising: a. a compressed gas supply capable of providing positive pressure gas, and b. a drive line in fluidic communication from said compressed gas supply to said gas port, and c. a valve capable of fluidically isolating said pressure sensor from said pump chamber, and d. a valve capable of fluidically isolating said compressed gas supply from said pump chamber.
 15. The fluid pump apparatus of claim 14, further comprising: a. a normally open check valve including a float, wherein said float is capable of allowing the bi-directional flow of gas and the downward flow of liquid, but preventing the upward flow of liquid.
 16. The fluid pump apparatus of claim 15, further comprising: a. a normally open check valve including a float, wherein said float is capable of allowing the bi-directional flow of gas and the downward flow of liquid, but preventing the upward flow of liquid.
 17. The fluid pump apparatus of claim 15, wherein: a. said output signal is capable of communicating with an intermediate device being at least one member of the group consisting of a number, a light, a level, a sound, a haptic response, and a different output signal.
 18. The fluid pump apparatus of claim 14, wherein: a. said exhaust chamber being at least one of a tank and atmosphere.
 19. The fluid pump apparatus of claim 12, further comprising: a. a compressed gas supply capable of providing positive pressure gas, and b. a drive line in fluidic communication from said compressed gas supply to said gas port, and c. a venturi in fluidic communication with said compressed gas supply and with said exhaust line, and d. a valve capable of fluidically isolating said venturi from said compressed gas supply, and e. a valve capable of fluidically isolating said pressure sensor from said pump chamber, and f. a valve capable of fluidically isolating said compressed gas supply from said pump chamber.
 20. The fluid pump apparatus of claim 12, further comprising: a. said pressure sensor positioned at least 30.5 m (100 ft.) above said pump chamber. 